Conventionally, a linear guide device used for a machine tool or the like generally includes a guide rail having rolling element orbital surfaces in its left and right side surface portions, a slider having in its inner side surface portions, rolling element orbital surfaces respectively facing the rolling element orbital surfaces of the guide rail, and multiple rolling elements which roll upon the relative linear motion of the slider or the guide rail in linear rolling element rolling paths formed between the rolling element orbital surfaces of the guide rail and the slider.
Upon rolling in the rolling element rolling paths, the rolling elements change their directions in end caps attached to the two ends of the slider in the front-to-rear direction, and then return to the original positions through rolling element return paths formed in the slider.
In such a linear guide device, when foreign particles such as dust enter the rolling element rolling paths from the gaps between the side surface portions of the guide rail and the inner side surface portions of the slider, the rolling motion of the rolling element is disturbed, leading to considerable degradation in travelling performance of the slider. Under the circumstances, a linear guide device including a seal which prevents foreign particles such as dust from entering the rolling element rolling paths from the gaps between the side surface portions of a guide rail and the inner side surface portions of a slider has been proposed (see PTLs 1 and 2).
PTL 1 discloses a linear guide device including a seal formed on the bottom surface of the slider to prevent foreign particles such as dust from entering the rolling element rolling paths.
However, in the structure of the seal disclosed in PTL 1, the dustproof performance of the rolling element rolling paths may be insufficient, depending on the environment under which the linear guide device is used. To further enhance the dustproof performance in the rolling element rolling paths, a linear guide device with its dustproof performance reinforced by stacking bottom seals for the slider has been proposed, as in PTL 2.